The McDonald operation is used in a pregnant patient
with an incompetent cervix. It may be performed under local anesthesia
with minimal irritation to the uterus. It should be performed as early
in the pregnancy as possible and must be done prior to effacement and
complete dilation of the cervix.

Rupture of the membranes, leading to
the loss of the pregnancy, may be associated with the procedure. The
suture must be cut prior to labor to prevent severe laceration of the
cervix.

In the McDonald operation,
a suture is strategically placed to give additional strength to the
cervix and thereby prevent second-trimester abortion.

Physiologic Changes. By suturing the cervix, the
products of gestation are held in the uterine cavity until the fetus
is viable.

Points of Caution. Care must be taken not to lacerate
the soft pregnant cervix with the instruments.

The suture must be placed near the internal cervical os, but care must
be exercised not to enter the bladder with the suture anteriorly.

Technique

The patient, who may be given
light sedation with Demerol and Valium, is placed in the dorsal
lithotomy position. The vulva and vagina are prepped with a surgical
soap solution, and the weighted posterior retractor is placed
in the vagina to expose the cervix. An effort is made to place
a minimum of retraction instruments upon the cervix; if a retraction
instrument is needed, however, a wide-mouthed toothless instrument
such as a sponge forceps is preferable to a single-toothed cervical
tenaculum. A large, monofilament nonabsorbable suture, such as
Prolene or nylon is selected. The first bite of the McDonald
stitch is placed at the 12 o'clock position on the cervix at
the junction of the vaginal mucosa and portio of the cervix at
the level of the internal os.

Repeated pursestring sutures are placed in
4 or 6 bites around the cervix at the level of the internal os.

The pursestring suture is tied.

A cross section of the cervix reveals the
way the McDonald suture closes the internal os. The suture must
be cut prior to labor and delivery of the fetus.